The skull was found in a muddy pit unearthed during excavations on the site of the University of York's campus expansion at Heslington East and is thought to have been a ritual offering. Nobody is sure how the brain remained preserved for so long.

Here's how the noggin was first noticed: York Archaeological Trust dig team member Rachel Cubitt reached in and, while she cleaned the soil-covered skull's outer surface, "she felt something move inside the cranium. Peering through the base of the skull, she spotted an unusual yellow substance."

"The survival of brain remains where no other soft tissues are preserved is extremely rare," said Sonia O'Connor, research fellow in archaeological sciences at the University of Bradford. "This brain is particularly exciting because it is very well preserved, even though it is the oldest recorded find of this type in the U.K., and one of the earliest worldwide."

O'Connor called it the oldest brain found in Britain and "one of the earliest worldwide."

One might think the oldest preserved brains would come from Egyptian mummies, but the minds of mummies were typically removed and discarded.

"The brain was removed by carefully inserting special hooked instruments up through the nostrils in order to pull out bits of brain tissue," according to an Encyclopedia Smithsonian article on Egyptian mummies.

The mystery of the British brain's preservation could be cracked with more research. For instance, another oddity is that there was no skin or other tissue remaining, Duffey said.

"I think that it will be very important to establish how these structures have survived, whether there are traces of biological material within them and, if not, what is their composition," Duffey said.

It is not unheard of for soft biological tissue to be preserved over long periods of time. In 2005, scientists announced they had discovered 70-million-year-old Tyrannosaurus rexblood vessels. And the 5,200-year-old "Iceman" mummy, found in 1991 in the European Alps, has yielded a wealth of tissue.